This invention is concerned with a method for obtaining significant amounts of certain components of blood plasma.
The important components of blood plasma with which the process of this invention is primarily concerned are the anti-hemophilia factor (AHF), plasma fibronectin (cold-insoluble globulin-CIg) and von Willebrand's ristocetin cofactor. Components obtained according to the process of this invention are valuable in therapeutic applications. The AHF is known, of course, as the single significantly effective agent for use in treating hemophilia A.
It has been demonstrated in recent years that the fibronectin (CIg) component of human plasma is especially useful in speeding tissue recovery in trauma, particularly burns. The affinity of fibronectin to collagen and/or fibrin may be of significance in the mode of its action.
Von Willebrand's ristocetin cofactor is known to facilitate ristocetin mediated aggregation of platelets in patients with von Willebrand's disease.
The infusion of plasma fractions enriched with fibronectin has been effective in reducing general sepsis from severe trauma and burns. It has been found that a reduction in the body's level of fibronectin occurs following trauma, and that the sooner fibronectin is restored to normal levels, the faster recovery takes place; presumably related to an increase in the removal of damaged tissues, reduction of infection, and general wound healing.
Of concern to the growing application of fibronectin therapy is the depletion of plasma available for the isolation of AHF. This has vastly increased the need for an effective and efficient large scale process for separating plasma fractions of predominating fibronectin from the fractions of predominantly AFH activity.
Past methods have suffered from difficulties in effectively separating the desired constituents and isolating them on a large scale.
The present invention utilizes a number of individually known steps in combination with unique approaches to develop an overall process for the large scale isolation and purification of fibronectin (CIg), AHF, and von Willebrand's ristocetin cofactor from blood plasma.
The separation of such components by heparin precipitate has been carried out on only small scale levels of a milliliter of plasma up to one or two hundred milliliters of plasma. No satisfactory method has previously been developed for the processing of significant amounts of plasma such as over 0.5 liters and up to 1-5 liters.
It is well known that many unpredicted difficulties are usually encountered in attempting to scale up laboratory experimental procedures with plasma to even minimal commercial levels.
In the past, the attempted recovery of the fibronectin from the cryoprecipitate utilized phosphate and/or TRIS (hydroxmethyl-aminomethane type of buffer salts and resulted in low percentage recoveries of fibronectin.